1. Field of the Invention
The present invention relates to a novel processing aid for polycarbonate, and more particularly, relates to blends comprising polycarbonate and an effective amount of aliphatic C.sub.4 to C.sub.16 polyalpha olefin, functionalized aliphatic polyalpha olefin polymer or a hydrogenated polyalpha olefin.
2. Description of the Related Art
Aromatic polycarbonate resins have excellent mechanical strength, impact strength and heat resistance and, therefore, are used as engineering plastics in many fields. Improvement of processability by enhancing flow characteristics via adding processing aid is a typical practice in the development of plastics materials. However, the addition of processing aid, e.g. plasticizer, in polycarbonate often leads to a dramatic reduction of its impact strength. For example, when resorcinol diphosphate (RDP) or tetraxylylhydroquinone diphosphate (TXHQDP) is added to polycarbonate, the flow of polycarbonate is improved. However, the notched Izod impact strength of such a polycarbonate blend is decreased to as low as 1 ft-lb/in from 16 ft-lbs/in even when the loading of RDP or TXHQDP is as low as 4% of the total composition. The search of new solution to improve the flow without sacrificing other physical properties is a constant challenge in the development of polycarbonate blends.
This and other objects hereinafter appearing have been achieved in a general sense in accordance with the present invention through the discovery that by incorporating a small amount of an aliphatic C.sub.4 to C.sub.16 polyalpha olefin, specifically polybutene or an epoxy functionalized polybutene, into polycarbonate, the flow of the polycarbonate is substantially improved while maintaining the impact ductility as determined by Dynatup and Notched Izod tests.